Invasive Crayfish May Be Class Pets First

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Oregon has two new invasive species to deal with. For the first time in the western United States, scientists say two kinds of crayfish have appeared in streams and rivers.

What makes this story unusual is how they got here. Oregon Field Guide’s Vince Patton reports that it’s probably not anglers or boats spreading the crayfish. Instead, it may be your children.

This is a story of a river in eastern Oregon, a stream in the Willamette Valley and a pest.

Rusty Crayfish

Vince Patton / OPB

The invader they share in common got a helping hand from the most unlikely people.

Let’s start on the John Day River.

Julian Olden and a colleague are wrestling with a wide flat net.

They struggle to pull it down to the bottom of the riverbed.

Once it’s there, they shuffle their feet.

Within seconds they kick up what they’re looking for.

Julian Olden: “They’re pretty thick through here. Take a couple of kicks. It’s pretty much a crayfish under every rock. That’s the reality of it.”

Olden is an assistant professor with the University of Washington.

He’s finding rusty crayfish throughout 30 miles of river stretching downstream from the town of John Day. They don’t belong here.

Julian Olden: “This is the first known population west of the Continental Divide. This species are native to the upper Ohio River drainage in the Midwestern U.S.

It turns out the John Day isn’t the only new Oregon home for invasive crayfish.

There’s a small stream gurgling through Corvallis called Dixon Creek.

It also has rusty crayfish from the Midwest, plus Red Swamp crayfish from Louisiana.

So how do 2-inch long crustaceans climb the Rocky Mountains to reach the John Day River and then hike again over the Cascade Range to the Willamette Valley?

Anglers and their boats often introduce invasive species to new waters.

But they’re not the likely carriers this time.

Scientists realized that both the John Day River and Dixon Creek run behind several grade schools, which buy science kits that contain live crayfish.

Julian Olden:”Unlike the dominant vector which is through bait bucket releases of fishermen, we see a quite different story here. Crayfish are using the classroom.”

Every year, children at Franklin School in Corvallis get a hands-on lesson in biology. They feed and study live crayfish.

Their teacher, Jennifer England, says there’s no better way to engage kids than by having living examples in the classroom.

Jennifer England: “You can talk about it, you can look at a movie but it’s not the same as actually picking it up and learning how to, to hold the crayfish and what are the structures and how really unique are they.”

It’s when the lessons end that they cause problems.

Gregory Murphy studied crayfish for a whole semester.

Gregory Murphy: “And what happens in the classroom is people don’t know what to do with them so they’ll just release them into the wild and they won’t know they’re actually making an impact ecosystem.”

You see, Oregon has only one native crayfish. It’s called the signal crayfish.

Murphy has learned the signal doesn’t have a chance when aggressive crayfish from other parts of the country show up in local waters.

Gregory Murphy: “They will um, eat the fish eggs that are in the rivers and they will also kick the native crayfish out of their habitats.”